\begin{thebibliography}{}

\bibitem[\protect\citeauthoryear{Abiteboul}{1997}]{Abit97}
Abiteboul, S.
\newblock Querying Semi-Structured Data.
\newblock In Afrati, F. and Kolaitis, P., editors, {\em Proceedings ICDT '97,
  6th International Conference, Delphi, Greece}, volume 1186 of {\em Lecture
  Notes in Computer Science}, pages 1--18. Springer-Verlag, 1997.

\bibitem[\protect\citeauthoryear{Atkinson and Morrison}{1995}]{AtMo95}
Atkinson, M. and Morrison, R.
\newblock Orthogonally Persistent Object Systems.
\newblock {\em VLDB Journal}, 4(3), 1995.

\bibitem[\protect\citeauthoryear{Breazu-Tannen \bgroup \em et al.\egroup
  }{1991}]{BTBN91}
Breazu-Tannen, V., Buneman, P., and Naqvi, S.
\newblock Structural Recursion as a Query Language.
\newblock In {\em Database Programming Languages: Bulk Types and Persistent
  Data}. Morgan Kaufmann Publishers, September 1991.

\bibitem[\protect\citeauthoryear{Cattell}{1994}]{Catt94}
Cattell, R.G.G., editor.
\newblock {\em Object Data Management}.
\newblock Addison-Wesley Publishing Company, second edition, 1994.

\bibitem[\protect\citeauthoryear{CoFu}{1997}]{ColdFusion97}
Cold Fusion 3.0.
\newblock http://www.allaire.com, 1997.
\newblock Allaire Corp., One Alewife Center, Cambridge, MA 02140, USA.

\bibitem[\protect\citeauthoryear{Copeland and Maier}{1984}]{CoMa84}
Copeland, G. and Maier, D.
\newblock Making Smalltalk a database system.
\newblock In {\em Proceedings of the ACM-SIGMOD International Conference on
  Management of Data, Boston, Massachusetts}, pages 316--325, June 1984.

\bibitem[\protect\citeauthoryear{Fegaras}{1994}]{Fega94}
Fegaras, L.
\newblock Efficient Optimization of Iterative Queries.
\newblock In Beeri, C., Ohori, A., and Shasha, D.E., editors, {\em Database
  Programming Languages, New York City, 1993}, Workshops in Computing, pages
  200--225, 1994.

\bibitem[\protect\citeauthoryear{Gawecki and Matthes}{1996a}]{GaMa96a}
Gawecki, A. and Matthes, F.
\newblock Exploiting Persistent Intermediate Code Representations in Open
  Database Environments.
\newblock In {\em Proceedings of the Fifth Conference on Extending Database
  Technology, EDBT'96}, volume 1057 of {\em Lecture Notes in Computer Science},
  Avignon, France, March 1996. Springer-Verlag.

\bibitem[\protect\citeauthoryear{Gawecki and Matthes}{1996b}]{GaMa96b}
Gawecki, A. and Matthes, F.
\newblock Integrating Subtyping, Matching and Type Quantification: A Practical
  Perspective.
\newblock In {\em Proceedings of the 10th European Conference on
  Object-Oriented Programming, ECOOP'96}, pages 26--47, Linz, Austria, July
  1996. Springer-Verlag.

\bibitem[\protect\citeauthoryear{Goldfarb}{1991}]{Gold91}
Goldfarb, C.
\newblock {\em The SGML Handbook}.
\newblock Clarendon Press, Oxford, 1991.

\bibitem[\protect\citeauthoryear{HAHT}{1997}]{HAHTSite97}
HAHTsite 3.0.
\newblock http://www.haht.com, 1997.
\newblock HAHT Software, Inc., 4200 Six Forks Road, Raleigh, NC 27609, USA.

\bibitem[\protect\citeauthoryear{HOX}{1997}]{HOX97}
Higher-Order Informations- und Kommunikationssysteme GmbH.
\newblock http://www.higher-order.de, 1997.
\newblock Burchardstra{\ss}e 19, D-21071 Hamburg, Germany.

\bibitem[\protect\citeauthoryear{ISO8879}{1986}]{ISO8879}
{ISO 8879}, Geneva.
\newblock {\em Information Processing -- Standard Generalized Markup Language},
  1986.

\bibitem[\protect\citeauthoryear{LiWi}{1997}]{LiveWire97}
Netscape LiveWire.
\newblock http://www.netscape.com, 1997.
\newblock Netscape Communications Corporation, California, USA.

\bibitem[\protect\citeauthoryear{Matthes and Schmidt}{1991}]{MaSc91b}
Matthes, F. and Schmidt, J.W.
\newblock Bulk Types: Built-In or Add-On?
\newblock In {\em Database Programming Languages: Bulk Types and Persistent
  Data}. Morgan Kaufmann Publishers, September 1991.

\bibitem[\protect\citeauthoryear{Matthes}{1997}]{Matt95}
Matthes, F.
\newblock Higher-Order Persistent Polymorphic Programming in {Tycoon}.
\newblock In Atkinson, M.P., editor, {\em Fully Integrated Data Environments}.
  Springer-Verlag (to appear), 1997.

\bibitem[\protect\citeauthoryear{MSQL}{1997}]{MSQL97}
W3-msql.
\newblock http://Hughes.com.au, 1997.
\newblock Hughes Technologies, Inc., PO Box 432, Main Beach, Gold Coast Qld
  4217, Australia.

\bibitem[\protect\citeauthoryear{NCSA}{1997}]{NCSA97}
The NCSA HTTPd.
\newblock http://www.ncsa.uiuc.edu, 1997.
\newblock The National Center for Supercomputing Applications, University of
  Illinois at Urbana-Champaign.

\bibitem[\protect\citeauthoryear{NetD}{1997}]{NetDynamics97}
NetDynamics 3.1.
\newblock http://www.w3spider.com, 1997.
\newblock NetDynamics, Inc., 185 Constitution Dr., Menlo Park, CA 94025, USA.

\bibitem[\protect\citeauthoryear{Roxen}{1997}]{Roxen97}
Roxen WWW Server.
\newblock http://www.roxen.com, 1997.
\newblock Roxen InformationsV\"avarna AB, Skolgatan 10, S-582 35 Link\"oping,
  Sweden.

\bibitem[\protect\citeauthoryear{Schmidt and Matthes}{1994}]{ScMa94}
Schmidt, J.W. and Matthes, F.
\newblock The {DBPL} Project: Advances in Modular Database Programming.
\newblock {\em Information Systems}, 19(2):121--140, 1994.

\bibitem[\protect\citeauthoryear{van Herwijnen}{1994}]{Herw94}
Herwijnen, E. van.
\newblock {\em Practical SGML}.
\newblock Kluwer Academic, 2nd edition, 1994.

\bibitem[\protect\citeauthoryear{WebO}{1997}]{WebObjects97}
WebObjects 3.0.
\newblock http://software.apple.com/webobjects, 1997.
\newblock 1 Infinite Loop, Cupertino, CA 95014, USA.

\end{thebibliography}